Patent attributes
A resin panel for an automobile includes a skin layer formed on sides of a package tray along the direction of the thickness of the package tray and both surfaces of the package tray substantially orthogonal to the sides. An expanded layer is formed in an inner part of the package tray surrounded by the skin layer having voids by enlarging the volume of the cavity of a mold assembly during molding of the package tray to expand a thermoplastic resin in the cavity. Hollow ribs are formed of solid layers in the expanded layer to extend along the surfaces, each have a hollow formed inside over the entire length so that ends of the hollow rib continue out to the skin layer at the opposed sides of the panel. Openings in communication with the hollow rib are formed through the skin layer at the opposed sides, respectively.
